ddo/abstraction/
fringe.rs

1// Copyright 2020 Xavier Gillard
2//
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4// this software and associated documentation files (the "Software"), to deal in
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19
20use crate::SubProblem;
21
22
23/// This trait abstracts away the implementation details of the solver fringe.
24/// That is, a Fringe represents the global priority queue which stores all 
25/// the nodes remaining to explore.
26pub trait Fringe {
27    type State;
28
29    /// This is how you push a node onto the fringe.
30    fn push(&mut self, node: SubProblem<Self::State>);
31    /// This method yields the most promising node from the fringe.
32    /// # Note:
33    /// The solvers rely on the assumption that a fringe will pop nodes in
34    /// descending upper bound order. Hence, it is a requirement for any fringe
35    /// implementation to enforce that requirement.
36    fn pop(&mut self) -> Option<SubProblem<Self::State>>;
37    /// This method clears the fringe: it removes all nodes from the queue.
38    fn clear(&mut self);
39    /// Yields the length of the queue.
40    fn len(&self) -> usize;
41    /// Returns true iff the fringe is empty (len == 0)
42    fn is_empty(&self) -> bool {
43        self.len() == 0
44    }
45}
ddo/abstraction/fringe.rs

ddo/abstraction/
fringe.rs
